Blue and green are similar in hue. Before the modern period, Japanese had just one word, Ao, for both blue and green. The wall that divides these colors hadn’t been erected as yet.

One of the first fences in this color continuum came from crayons. In 1917, the first crayons were imported into Japan… There were different crayons for green (midori) and blue (ao), and children started to adopt these names. But the real change came during the Allied occupation of Japan after World War II, when new educational material started to circulate. In 1951, teaching guidelines for first grade teachers distinguished blue from green, and the word midori was shoehorned to fit this new purpose.

There are clues that remain in the language, that bear witness to this awkward separation. For example, in many languages the word for vegetable is synonymous with green (sabzi in Urdu literally means green-ness, and in English we say ‘eat your greens’). But in Japanese, vegetables are ao-mono, literally blue things. Green apples? They’re blue too. As are the first leaves of spring, if you go by their Japanese name.

Wwhat really is a color? Just like the crayons, we’re taking something that has no natural boundaries – the frequencies of visible light – and dividing into convenient packages that we give a name.

But if you think about it, there’s a real puzzle here. Why should different cultures draw the same boundaries? If we speak different languages with largely independent histories, shouldn’t our ancestors have carved up the visual atlas rather differently?

This question was first addressed by Brent Berlin and Paul Kay in the late 1960s. They wanted to know if there are universal, guiding laws that govern how cultures arrive at their color atlas.

And here’s what they found. Languages have differing numbers of color words, ranging from two to about eleven. Yet after looking at 98 different languages, they saw a pattern. It was a pretty radical idea, that there is a certain fixed order in which these color names arise. This was a common path that languages seem to follow, a road towards increasing visual diversity.

If a language has just two color terms, they will be a light and a dark shade – blacks and whites. Add a third color, and it’s going to be red. Add another, and it will be either green or yellow – you need five colors to have both. And when you get to six colors, the green splits into two, and you now have a blue. What we’re seeing here is a deeply trodden road that most languages seem to follow, towards greater visual discernment.

Something eerily powerful is at work here. These cultures have largely independent histories, yet they somehow gravitate towards the same choices for how to slice up the visual cake.

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If that old chestnut about the Inuit having 30 words for snow were applied to Proto-Indo-European speaking peoples, their language, spoken roughly 6000 years ago, would reveal a fascination for two phenomenon: all thing swelling and all things shiny. Our contemporary infatuation with Foxconn baubles suggests we haven’t changed much concerning the latter; we’re still little different from magpies in that regard.

Various words for colours have their etymological roots in words meaning “shiny”, or lack of shininess, and some contrasting hues even have the exact same origin.

The word “black” and words in various languages for “pale” or “to whiten”, such as the English “bleach” and the French blanc, have the same etymological origin that meant “to burn” or “to shine”. And while the English “pale” has a different origin, it is the same one as the Greek pelios “livid, dark”, and is related to the O.E. fealo, “dull-colored, yellow, brown”. The origin of the word “white” was another word meaning “to shine, to brighten”.

The word “brown” comes from a word meaning “”shining, brown”. The word “blue” from a word meaning “light-colored, blue, blond, yellow”, but it is related to the origin which gave us “black” meaning “to burn” and “to shine”. The word “yellow” from a word that meant “yellow, green”.

The Japanese conflation of blue and green (they still say a traffic light is blue) was common in various Indo-European languages as well, and stems from the designation for the gray-blue-green colour of the sea.

The only colour with an origin that meant one unambiguous colour (by contemporary standards), instead of a vague range, is red. Most mammals cannot detect the colour red, primates developed trichromacy in order to detect ripe fruit when living in the forest canopy. The survival of our ancestors depended on discerning the colour red.